1844

[The Dowager Mod]

What if Clay had won?
would the civil war have happened sooner, later or not at all?

[PBrunsel]

Clay opposed Texas anexation, but wanted Oregon. I see a war with Britain, "The Oregon War."

[The Dowager Mod]

54 40 or fight!

[PBrunsel]

54 40 or fight!

I bet we would have lost land.

I think the British would have invaded, taken Buffalo, NY, quite easily, and the Battle of the Erie Canal would have been quite a fight.

Though President Clay would have made peace before the Brits took D.C.

Generals Taylor and Scott would have been made heroes fighting in Canada, and one would have defeated an unpopular President Clay in the Whig Primary of 1848.

[The Dowager Mod]

Which brings up a different question since clay died  on June 29, 1852.
president Frelinghuysen?

[True Federalist (진정한 연방 주의자)]

I don't think that we would have had a war of any sort with Clay as President.  We probably would have had an annexation of a Texas Republic that would have the Nueces River as its southern boundary.

[The Dowager Mod]

We would have fought Mexico over california and the rest eventually.

[True Federalist (진정한 연방 주의자)]

Assuming that the Union stays intact., you may be right.  If Clay or another non-southwestern president gets elected in 1848, then I can see a Southern secession occurring, and likely with no Civil War.

[M]

By 1844, we can tackle Britain alone on land, but bring in Mexico and we're in trouble.

A 54'40 scenario without Texas annexation could be interesting... You might get a U.S. grabbing Canada, pro-slavery Scott administration 48-56 presidency annexes Texas (where Houston has returned as president, now governor) and wins a war with Mexico, annexing the whole thing. Houston-Davis administration, Whig party decays but the moderate Houston keeps the country together. After his death in '63, Davis runs for reelection and narrowly beats Seward. Crittenden amendment passes, and Crittenden is Jeff Davis's veep... Mexico unhappy with enforced slavery, and Fremont led a California rebellion which got him disgraced and imprisoned. Anyway, Davis-Crittenden reelectedin '64, buy Alaska (Breckenridge's Icebox?) and Greenland; Central America absorbed. In '68 Thad Stevens (the Republicans got angry and went to radical) and Crittenden are beaten by Zebulon Vance, the last Whig. Cuba purchased, Hispaniola annexed. In '72 Old Abe Lincoln came out of the wilderness, and a Confederacy led by old Judah Benjamin declares war... supported by Disraeli's UK. It's the minimal Confederacy- SC, Georgia, Alabama, Mississippi, Florida, and Louisiana. Union armies- led by W.T.Sherman in the west and Stonewall Jackson in the East- blitz the South. In the ensuing naval war with Britain we start off in trouble, but Farragut's navy regroups and eventually gains local dominance. Caribbean, Bermuda, acquired through purchases and the peace treaty with Britain. Britain acquires the Faeroes and Iceland as a special self-governing dominion to counter the new American threat (Denmark is feeling very pushed around now). Lincoln reelected in '76, thanks partly to Reconstruction, though Lincoln's reconstruction is quite light. In '80 the Union general George Armstrong Custer beats former Confederate Joe Wheeler. The Civil war was quite a bit lighter (smaller Confederacy, much more industrialized North) and reconstruction was less harsh; the country's divisions are much less intense and Manifest Destiny is back with a vengeance. For Custer, there's still a lot of Manifest Destiny to be fulfilled... a whole 'nother America to the south of Panama State.

So, we have
Clay (W) '44-'48
Oregon, Canada acquired

Scott (W) '48-56
Texas, Mexico acquired

Houston (D) '56-'63
Crittenden amendment passed, Central America acquired

Davis (D) '63-'68
Alaska, Greenland acquired

Vance (W) '68-'72
Cuba, Hispaniola acquired

Lincoln (R) '72-80
Civil War; Caribbean, Bermuda acquired

Custer (R) '80-
South America is in trouble